A191480 Number of n X n symmetric binary matrices with each 1 adjacent to no more than 4 king-move neighboring 1's.

2, 8, 51, 624, 14937, 660986, 54708660, 8491650283, 2464559025659, 1339399598735349, 1362655720519108653, 2594569727636065556778, 9247397059247356652311714, 61693653372161864968465187134

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..16

Example

Some solutions for n=4
..0..0..0..0....0..0..1..0....1..1..0..0....0..0..1..0....0..0..1..0
..0..1..0..0....0..0..1..1....1..0..1..1....0..1..0..0....0..0..0..0
..0..0..1..0....1..1..0..0....0..1..0..0....1..0..1..0....1..0..1..1
..0..0..0..0....0..1..0..1....0..1..0..1....0..0..0..1....0..0..1..1

Crossrefs

Sequence in context: A277506 A059429 A249747 * A013555 A018987 A030518

Adjacent sequences: A191477 A191478 A191479 * A191481 A191482 A191483

Keyword

nonn

Author

R. H. Hardin, Jun 03 2011

Status

approved